Envisager, vt : to contemplate, to consider.
Envisager de faire quelque chose, loc v : to think of doing something, to think about doing something, to consider doing something.
Envisager le pire, loc v : to consider a worst-case scenario, to assume the worst.

Il faut envisager toutes les solutions possibles.
All possible solutions have to be contemplated.

Est-ce que vous envisagez de travailler à l’étranger?
Are you considering working abroad?

Nous envisageons de déménager à la campagne.
We are thinking of moving to the country.

N’envisageons pas le pire. Tout ira bien.
Let’s not assume the worst. Everything will be fine.